#include <bits/stdc++.h>

using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
typedef pair<int,int> pii;
int n,m,niv[100005],bestniv[100005],parent[100005];
vector<int> muchii[100005];
bool use[100005];
stack<pii> stiva;
vector<vector<int>> sol;
void build(int a,int b)
{
    if(a>b)
        swap(a,b);
    vector<int> v;
    while(!stiva.empty())
    {
        pii x=stiva.top();
        if(x.first>x.second)
            swap(x.first,x.second);
        v.push_back(x.first);
        v.push_back(x.second);
        stiva.pop();
        if(x.first==a&&x.second==b)
            break;
    }
    sort(v.begin(),v.end());
    v.erase(unique(v.begin(),v.end()),v.end());
    sol.push_back(v);
}
void dfs(int nod,int par)
{
    use[nod]=1;
    if(nod==1)
        niv[nod]=1;
    bestniv[nod]=niv[nod];
    for(auto i:muchii[nod])
    {
        if(i==par)
            continue;
        if(!use[i])
        {
            stiva.push({i,nod});
            niv[i]=niv[nod]+1;
            parent[i]=nod;
            dfs(i,nod);
            bestniv[nod]=min(bestniv[nod],bestniv[i]);
            if(niv[nod]<=bestniv[i])
                build(i,nod);
        }
        else
            bestniv[nod]=min(bestniv[nod],niv[i]);
    }
}
int main()
{
    ios_base::sync_with_stdio(false);
    fin.tie(0);
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int a,b;
        fin>>a>>b;
        muchii[a].push_back(b);
        muchii[b].push_back(a);
    }
    dfs(1,0);
    fout<<sol.size()<<'\n';
    for(int i=0;i<sol.size();i++,fout<<'\n')
        for(int j=0;j<sol[i].size();j++)
            fout<<sol[i][j]<<' ';
    return 0;
}